Apparatus for cleaning trays and the like

ABSTRACT

An apparatus for cleaning material from trays and the like disposed in substantially upright dumping position including a conveyor for successively placing trays at a scraping station and removing them therefrom, and a pivotally mounted scraper movable into engagement with the successive trays and removable therefrom having elements to which a cyclic scraping motion is imparted, the conveyor and scraper being actuated sequentially by drive mechanisms driven differentially from a common source of power.

United States Patent Lazar et al.

[451 Apr. 25, 1972 APPARATUS FOR CLEANING TRAY AND THE LIKE Inventors: Harvey B, Lazar, PO. Box 73; Frank J.

Andrews, 1066 South 1st, both of Turlock, Calif. 95380 Filed: Mar. 27, 1969 Appl. N0.: 811,137

U.S. CL... ..15/93 Int. Cl. ..B67c 1/10 Field of Search ..l5/93, 77, 74, 56, 21, 4,102,

l5/97, 97 A, 33; l34/43, 46

References Cited UNITED STATES PATENTS 10/1947 Sanders et a1 "15/93 5/l 953 Moore 2,802,227 Parsons l5/93 834,766 10/1906 Smith 1,278,848 9/1918 Burkhart....

3,223,097 12/ 1 965 Spaulding ..134/46 Primary Examiner-Leon G. Machlin .JiilQK'lQ .i sb e &.. l rrgl ABSTRACT An apparatus for cleaning material from trays and the like disposedin substantially upright dumping position including a conveyor for successively placing trays at a scraping station and removing them therefrom, and a pivotally mounted scraper movable into engagement with the successive trays and removable therefrom having elements to which a cyclic scraping motion is imparted, the conveyor and scraperheing actuated sequentially by drive mechanisms driven differentiallyfrom a common source of power.

20 Claims, 26 Drawing Figures Patented April 25, 1972 3,657,758

10 Sheets-Sheet 1 HARVEY B. LAZAA F RANK J ANDREWS IN Vf N T095 MfM ATTORNEYS Patented April 25, 1972 10 Sheets-Sheet 2 QM ME HARVEY B. LAZA/P FRANK J. ANDREWS I IN VE N TORS M0 7M A TTOPNEVS Patented April 25, 1972 3,657,758

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10 Sheets-Sheet 6 HARVEY B. LAZAR FRANK J. ANDREWS [NI/E N 70/?5 A TTO/PNEVS Patented April 25, 1972 3,657,758

10 Sheets-Sheet 7 g Mg ' HARVEY a. LAZAR KIWI? K8 R FRANK J. ANDREWS IN VF N TOPS MfM ATTORNEYS Patented April 25, 1972 10 Sheets-Sheet 8 HARVEY a. LAZAR FRANK J. ANDREWS INVE N 701?;

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10 Sheets-Sheet 10 19/6 Q 52 "m 60' 5o 56 6/? 54 HARVEY B. LAZAR FRANK J. ANDREWS INVENTORS A TTOIFWEVS BACKGROUND OF THE INVENTION The present invention relates to a cleaning apparatus and more particularly to such an apparatus for scraping material, such as raisins and the like from trays'therefor.

In the raisin industry, it is customary to place bunches of grapes in shallow containers or trays and to expose the grapes to the drying effects of a dehydrator or of the sun and air in a vineyard. After the grapes have dried into raisins, the trays are transported to a place where the raisins are transferred for further processing, such as cleaning, removal of stems, packing and the like. In such transfer, it is usual to place the tray in a generally upright position, tilted slightly from the vertical, so that the loose raisins gravitate into a receptacle from which they are conveyed for further processing. However, because raisins frequently exude sugar, many of the raisins adhere to the surface of the tray and do not fall therefrom when it is placed in a dumping position. Under such conditions, it is necessary to scrape the tray by hand in order to minimize waste of the raisins and to condition the trays for reuse. Conventionally, the effort required to scrape the containers or trays clean involves labor which is tedious and time consuming and necessitates the use of additional workmen, thereby increasing the cost of processing the raisins.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus for automatically cleaning material from trays and the like in a rapid and reliable manner.

Another object is to provide a cleaning apparatus operatively related to a tray conveying system for minimizing the labor required to separate material from the trays.

Another object is to provide an automatic apparatus for separating material from material carrying trays.

Another object is to provide a cleaning apparatus which is differentially driven for sequentially placing the apparatus in operative relation to a tray, performing a cleaning function while so related, and retracting the apparatus.

Another object is to provide a scraping apparatus having scraping elements which are expansible upon engagement with a tray for effecting a scraping function thereon in a more efficient manner.

These and other objects and advantages of the present invention are achieved by providing an apparatus which includes a conveyor chain supporting a material carrying tray in substantially upright dumping position and carrying the tray to a scraping station where a pivotally mounted scraping device is moved into engagement with the tray. The device has articulated scraping elements which expand when placed in contact with the tray and to which a cyclic motion is impartedfor scraping the tray and separating adherent material therefrom. The separated material gravitates onto a material conveying system. The conveyor chain and scraping device are interconnected by drive mechanisms which are differentially driven from a common source of power and controlled for actuating the chain and the device sequentially in alternation. The controls include brake mechanisms and reciprocable latch means operatively related to a pair of rotary members alternately operable for effecting the movement and scraping motion of the scraping device. The apparatus also includes a mechanism for automatically returning the tray to material receiving positron.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan view of an apparatus embodying the principles of the present invention.

FIG. 2 is a side elevational view of the apparatus of FIG. 1.

FIG. 3 is an enlarged view of a portion of FIG. 1.

FIG. 4 is an enlarged view of a portion of FIG. 2.

FIG. 5 is a fragmentary elevational view, partly in section, of the left end of the portion of the apparatus shown in FIG. 4.

FIG. 6 is a fragmentary sectional view taken on line 6-6 of FIG. 5.

FIG. 7 is a perspective view of a container or tray used with the apparatus of the present invention, with parts broken away and in section to illustrate structural features thereof.

' FIG. 8 is an enlarged fragmentary vertical section taken on line 8-8 of FIG. 2.

FIG. 9is a fragmentary elevational view, partly in section, of

the right end of the portion of the apparatus shown in FIG. 4,

illustrating the disposition of the scraping .device in the retracted position thereof.

FIG. 10 is a fragmentary view somewhat similar to FIG. 9 but illustrating the scraping device in the extended position thereof in engagement with a container.

FIG. 11 is a fragmentary plan view of the scraping device viewed from line 11-11 of FIG. 10.

FIG. 12 is a fragmentary elevational view viewed from line 12-12 of FIG. 10.

FIG. 13 is a sectional view taken on line 1313 of FIG. 12.

FIG. 14 is a fragmentary side elevational view of a scraping mechanism.

FIG. 15 is an enlarged view of a portion of FIG. 14 illustrating the articulate connection of the scraping elements.

FIG. 16 is an enlarged fragmentary sectional view taken on line 1616 of FIG. 14 illustrating an adjustment device associated with a scraping element.

FIG. 17 is a schematic showing of an operating circuit of the apparatus.

FIG. 18 is a fragmentary elevational view of a portion of the apparatus illustrating the actuating and latching mechanisms for controlling one of the operating switches.

FIG. 19 is a fragmentary plan view of the mechanisms in FIG. 18.

' FIG. 20 is a fragmentary vertical sectional view taken on line 20-20 of FIG. 18.

FIG. 21 is an enlarged fragmentary perspective view of the I latching mechanism. I

FIG. 22 is an enlarged fragmentary view of a portion of FIG. 4 illustrating in greater detail the differentially driven rotary disks and associated latching mechanism for sequentially actuating the scraping device.

FIG. 23 is a fragmentary sectional view on line 23-23 of FIG. 22 illustrating the relationship between a rotary disk and a reciprocal latching bar in the unlocked condition of the disk.

FIG. 24 is an enlarged fragmentary sectional view of the rotary disk and latching bar in the locked condition of the disk.

FIG. 25 is a fragmentary elevational view, partly in section, of the bar and disk of FIG. 24. I I

FIG. 26 is a fragmentary vertical sectional view on line 26- 26 of FIG. 25 illustrating the cams and locking recess carried by the disk.

DESCRIPTION OF THE INVENTION Referring to the drawings, there is shown in FIGS. 1 and 2 an apparatus embodying the principles of the present invention and designated generally by reference numeral 30. The apparatus includes an elongated support or frame 32 mounted on a floor or base 34. Supported on the frame is a container receiving or loading station 36, a container treating or scraping station 38, an inspection station 40 and a container discharge station 42.

Mounted for movement on the frame lengthwise thereof is an endless conveyor chain 44 which terminates short of the discharge station and is adapted to be driven so that the upper run of the chain moves in the direction of the arrow 46. At the treating station, pivotally mounted on a portion of the frame is a scraping device 48 which is linked-to and actuated by a pair of rotary members or disks 50 and 52 in a manner hereinafter described.

As best seen in FIG. 3, the disk 50 is connected to the outer end of an axle shaft 54 and the disk 52 is connected to the outer end of an axle shaft 56. The disk 52 is normally held against rotation by a latching bar 58 engaged therewith through a latch 60 formed on the inner side face of the disk, as

shown in FIG. 4. The latching bar is adapted to be disengaged from the disk 52 and to be engaged with the disk 50 through a latch 60' formed on the inner side face of the latter disk. The latches will subsequently be described in greater detail.

The inner ends of the axle shafts 54 and 56 are interconnected by a conventional differential transmission gearing 61 contained in a housing 62 mounted on the frame portion. The gearing is illustrated schematically only and not in detail. Connected to the gearing 61 is a pulley 63 which is connected by belting 64 to a pulley 66. The pulley 66 is secured to the outer end of an axle shaft 68 adapted to be driven by a conventional differential transmission gearing 70, shown schematically only and contained in a housing 72 mounted on the frame portion. The gearing 70 is also adapted to drive an axle shaft 74 and is connected by a belt 76 and pulleys 78 and 80 with a drive shaft 82 connected to a source of rotary power, such as an electric motor 84 or the like, supported on the frame portion.

Referring also to FIG. 5, secured to the outer end of the axle shaft 74 is a sprocket 86 connected by a chain 88 to a sprocket 90 on a shaft 92 mounted for rotation in the frame. Secured to the shaft 92 is a drive sprocket 94 to which an idler 96 mounted on the frame is operatively related so as to train the conveyor chain 44 thereabout, as shown in FIGS. 4 and 6.

Also secured to the axle shaft 74 is a brake drum 98, the rotation of which is controlled by a suitable braking mechanism linkage 100 actuated by a solenoid 102 mounted on the frame portion, best seen in FIG. 6. Energization of the solenoid thus results in stopping rotation of the axle shaft 74 and the conveyor chain 44 and causes rotary power delivered to the differential gearing 70 to be transmitted to the axle shaft 68.

Secured to the shaft 68 is a brake drum 104 controlled by a braking mechanism linkage 106 to which are connected a solenoid 108 and one end of a tension spring 110, as shown in FIG. 4. The other end of the spring is anchored to the frame portion so that the spring biases the linkage 106 to stop rotation of the drum 104. When the solenoid 108 is energized it pulls on the linkage 106 against the bias of the spring 110 and releases the drum 104 for rotation.

Referring to FIG. 7, there is shown one form of a shallow containeror tray 112 used with the apparatus of the present invention. The tray can be formed to provide a rectangular plate or sheet of material 114 having end edges each of which is sandwiched between a pair of end cleats 116. Abutting the other edges of the sheet material are longitudinal bars 1 18 the ends of which are received between the ends of the pairs of cleats 116. For additional strength and rigidity, a pair of intermediate cleats 120 can be provided which are suitably secured to the sheet material and the bars. Crossbars 122 secured to the bars 1 18 provide additional support for the container.

A tray 112 to be treated or scraped is placed on the apparatus 30 at the receiving or loading station 36 thereof. The tray is disposed in generally oblique position tilted slightly forwardly from the vertical, as shown in FIG. 5, so that material M thereon which is loosegravitates onto the upper run of an endless belt conveyor 124 supported on the frame below the conveyor chain 44 and flanked by sloping side plates 126. The conveyor 124 extends through the treating station 38 and is suitably driven by a motor mechanism 128 so as to discharge the material M onto a transversely disposed conveyor 130, as shown in FIG. 4. The conveyor 130 is shown fragmentarily in FIG. 1 and serves to carry the material away for further processing.

The tray is rested on the upper run of the conveyor chain 44, with the bars 118 disposed generally horizontally, and is maintained in its tilted position by an upper angle iron 132 supported on the frame. The angle iron is substantially coextensive with the conveyor chain 44 and has a depending leg 132a which engages the upper ends of the cleats 116 and 120 and the crossbars 122. Also supported on the frame is a lower angle iron 134 which is substantially coextensive with the chain and has an upright leg 134a aligned with the depending leg 132a of the angle iron 132, best seen in FIGS. 5 and 9.

At the treating station 38, a back-up plate 136 is secured to the frame generally parallel with the angle irons. A similarly supported back-up plate 1360 can be provided at the inspection station 40, which plate isv in effect an extension of the plate 136. Thus, with movement of the conveyor chain, the tray is drawn along the angle irons for disposal adjacent to the plate 136 for treatment and'then conveyed through the inspection station 40 and eventually to the discharge station 42.

At the discharge station, the tray is removed from the conveyor chain and is swung from its tilted position onto a conveyor 138, fonned of a pair of endless belts, for disposition in a material receiving position. For this purpose, a pair of idler rollers 140 and 142 and a driven roller 144 are mounted for rotation on the frame in spaced relation, with the uppermost points of the peripheries thereof disposed generally in a plane, as shown in FIG. 2, slightly above the conveyor 138. The rollers are also longitudinally aligned with the conveyor chain and so positioned relative to the end thereof that the chain is adapted to propel a tray over the roller 140 into engagement with the roller 144. The roller 144 is made of suitable material, such as rubber or the like, for taking over propulsion of the tray and advancing it over the roller 142 into engagement with the end of the frame. The lower end of the tray is thus supported solely on the rollers. The roller 144 is driven through a suitable drive connection 146 by a motor 148 mounted on the frame.

As shown in FIG. 8, there is provided a kicker plate 150 having spaced arms 152 affixed to the upper end thereof, each arm being connected to the frame by a pivot pin 154. The pivot pins are axially aligned to support the plate for swinging about a horizontal pivot axis. At its upper end, the plate has an angular portion 156 with a depending leg 1560 which are longitudinally aligned with the angle iron 132 and leg 132a, respectively, and function similarly to maintain the upper end of the tray in place.

For imparting swinging movement to the kicker plate, it is provided with a pair of stiffening ribs 158 to which the ends of a pair of links 160 are pivotally connected, the other ends of the links being connected to a pair of bell cranks 162. Each bell crank is pivotally mounted on the frame-by a pivot pin 164, one arm thereof being pivoted to a link 160 and its other arm connected to a solenoid 166 mounted on the frame. The solenoids are energized by a circuit, not shown, through the closure of a switch 168 mounted on the frame end, as shown in FIG. 2, which-switch is closed when the tray is in abutting engagement therewith. When the solenoids are energized, the bell cranks are pivoted to swing the kicker plate to the right, as viewed in FIG. 8, to the position shown in dashed lines. This moves the lower end of the tray off of the supporting rollers and the tray gravitates into engagement with the conveyor 138. The conveyor is driven so that the upper runs of the endless belts move in the direction of the arrow 170 to carry the lower ends of the trays past a vertical line extending from the leg 156a and to swing the trays, as shown in dashed lines in FIG. 8. The upper ends of the trays slide down the kicker plate and eventually are disposed on the conveyor with the material receiving sides thereof uppermost. Tension springs 172 interconnect the frame and the ribs and serve, when the solenoids 166 are deenergized, to return the plate to the normal position shown in full lines in FIG. 8.

Referring to FIGS. 9 and 10, the scraping device 48 includes an elongated support block having a pair of aligned pivot shaft ends 182 supported in a pair of spaced bearing mounts 184 suitably secured to the frame portion, as shown in FIG. 11. Attached to the ends of the support block and depending therefrom are a pair of parallel angle irons 186, as shown in FIG. 12. Each angle iron has fixed thereto a bent wing plate 188 of a length to pass between the angle irons 132 and 134, as shown in FIGS. 10 and 12. The wing plates are spaced so that the distal ends thereof can move past the ends of the back-up plate 136, as shown in FIG. 13.

Pivotally connected to one of the angle irons 186 is one end of a connecting rod or pitman 190, the other end of which is pivoted to the rotary disk 50. Thus, with a half-revolution turn of the disk, the wing plates 188 are swung from the retracted position shown in FIG. 9 to the extended position shown in FIG. 10.

Mounted for movement on the support block 180, lengthwise thereof, is a carriage member 192 having laterally extending legs 194 mounting opposed projections 196 which extend into elongated notches 198 formed in the upper and lower edges of the block and are slidable therein. The carriage member is also provided with a plurality of cars 200 on which are mounted rollers 202 engaging the upper and lower edges of the support block. Pivotally connected to the carriage member, as at 204 in FIG. 11, is one end of a connecting rod or pitman 206, the other end of which is pivoted by a connection 208 to the underside of a quadrant or sector plate 210, as shown in FIGS. 5 and 12. The sector is pivotally mounted on the frame portion, as at 212, with the pivotal connection 208 spaced a predetermined distance from the pivotal mount. Also spaced at predetermined distances from the pivots 208 and 212 is a pivotal connection 214 to which is connected one end of a connecting rod or pitman 216, the other end of the rod being pivotally connected to the rotary disk 52. The various dimensions are so predetermined that rotation of the disk 52 serves to swing the sector plate about its pivotal mounting 212 for imparting a cyclic movement to the carriage member 192 between the limits defined by the angle irons 186, as shown in FIG. 12.

Afiixed to the carriage member 192 are spaced pairs of mounting projections 218 for mounting scraping mechanisms 220 thereon. Each mechanism has a bifurcated connector 222 to which is affixed a pair of depending plates or straps 224. The connector is secured to the mounting projections by bolts 226. The plates 224 are held in spaced relation by a fixture 228 at the distal ends thereof and a pair of spacers 230, as shown in FIG. 14.

Each pair of plates slidably receives therebetween a plurality of scraping elements or blades 232, 234 and 236. The intermediate blade 234 is disposed between the spacers in slidable engagement therewith and has extensions 238. The adjacent ends of the blades 232 and 236 also have extensions 240 and 242, respectively, which overlap the respective extension 238. Thus, the blades are substantially aligned coextensively with the plates. The back of each blade is provided with a pair of stop pins 244 which limit movement of the blade.

Each blade has associated therewith a pair of adjustment devices 246 operable to bias the blade stop pins into plate engagement. Referring to FIG. 15, each adjustment device includes a hollow mounting post 248 one end of which is slotted, as at 250, to provide a pair of legs 252 the ends of which are fixed to the plates astride the back edge of the blade, as shown in FIG. 16. The blade edge is slidably received in the slot and is engaged by one end of a compression spring 254 within the post. The other end of the spring is engaged by an adjusting bolt 256 threadedly connected to the other end of the post so that turning of the bolt adjusts the compression of the spring.

Returning to FIG. 14, secured to the intermediate pair of posts 248 associated with the blade 234 is a bridge member 258 having ends extending therebeyond and carrying pins 260 pivotally connecting hollow links 262 and 264 thereto. The distal end of the link 262 is bifurcated and formed with elongated openings or slots 266 in which is received a cross pin 268 fixed in the back of the end blade 232 to provide a lost motion mechanism. As shown in FIG. 15, disposed within the link 262 is a compression spring 270 mounted to react against the blade back edge and bias the cross pin to a normal position at the distal ends of the link slots. The link 264 is similarly provided with a spring and slots pinned to the end blade 236. The blades are thus articulately interconnected so that when pressed against a tray, the blades move transversely of the plates 224 and the end blades also slide lengthwise to extend the full distance between the bars 118 of the tray 112, as will be appreciated by observing FIG. 14.

To minimize the adherence to the scraping blades of the material being scraped and to condition the blades for a scraping action, there is provided a conditioning device 272 which is operatively engaged with the scraping blades in the retracted position of the scraping device 48, as shown in FIG. 9. As best seen in FIG. 10, the blade conditioning device includes a lower horizontal crosspiece 274 and an upper horizontal crosspiece 276 supported on the frame portion. Referring also to FIG. 11, mounted on the crosspiece 274, and upstanding therefrom, are pairs of backing plates 278 equal in number and spacing to the scraping mechanisms 220 so that the scraping blades thereof are received therebetween when the scraping device is in the retracted position. The upper ends of the backing plates are connected by braces 280 to the upper crosspiece 276. The facing sides of each pair of backing plates support laterally extending flexible fingers or bristles 282, the distal ends of which are contiguous and are adapted to engage the scraping blades and sweep therefrom adhering material as the blades move into engagement with the bristles upon movement of the scraping device to its retracted position.

The bristles can also be utilized to apply a conditioning fluid, such as water and the like, to the scraping blades. For this purpose, each set of bristles has associated therewith a faucet 284 or the like suitably supported on an associated brace. The faucets are connected by ducting 286 with a supply of fluid, not shown. Each faucet is adjusted to drip an optimum amount of fluid onto the bristles to maintain them in a moist condition for conditioning the blades.

If desired, a receptacle, not shown, can be provided below the conditioning device 272 to receive any fluid dripping therefrom and any material swept or brushed from the scraping blades.

In order to perform a scraping operation, it is desirable that the tray be held stationary at the scraping station a time sufficient for the scraping device to be engaged with the tray, is scraping motion be imparted to the blades thereof, and the scraping device be withdrawn. For this purpose, the solenoids 102 and 108 are incorporated into an operating circuit, as shown in FIG. 17. The coil of the solenoid 102 is connected to a source of electrical power 288 by a lead 290. Connected to the coil of the solenoid 108 are leads 292 and 294, the former going to the coil of the solenoid 102 and the latter to one of a pair of spaced contacts 296 and 298 adapted to be bridged by a shorting bar 300 forming part of a normally open relay 302. The contact 298 is connected to the power source by a lead 304. Thus, when the relay is energized, the bar bridges the contacts to complete the circuit to the solenoids and energize them. When the solenoids are energized, the brake drum 98 and the conveyor chain 44 are stopped and the brake drum 104 is released for the transmission of rotary power to the differential gearing 62 and the rotary disk 50.

The relay is energized by means of circuitry including normally open switches 306 and 308, connected by a lead 310 to the relay, and a normally open switch 312 having a lead 314 going to the relay. A lead 316 connects the switch 312 to one side of the power source and a lead 317 connects the switches 306 and 308 to the other side thereof. Associated with the switch 306 is a pivoted plate 318 adapted to be swung by the action of a tray to close the switch for completing the circuit to the relay. The relay circuit is also completed by closure of the switch 308 by the action of a cam portion 320 formed on the periphery of the rotary disk 50. operatively related to the switch 312 is a pivoted member 322 normally resting on the switch for holding it closed but adapted to be engaged by a traveling tray and lifted for opening the switch and breaking the circuit to the relay for preventing energization thereof. This is to insure that the relay is not energized until the tray is properly in place for scraping.

As shown in FIG. 18, the plate 318 is hinged to the frame, as at 324, and carries a pad 326 engageable with the switch 306. A spring 328 reacts between the frame and the plate so that the switch is normally open. The plate 318 is adapted to be pivoted to close the switch 306 through the action of a traveling tray against a contact plate 330 fixed to an actuating bar .332, best seen in FIGS. 19 and 20. The actuating bar is connected by a pivot pin 334 to a-support 336 which has a pivot shaft 338 joumaled in a bracket 340 secured to the frame. The axes of the pivot pin and shaft are perpendicular so that the bar can swing generally inline with the frame and transversely thereof, as shown in FIG. 20. A tension spring 342, interconnected between the bar and the frame, biases the bar to a normal position out of engagement with the plate 318, as shown in FIG. 18. In the normal position of the bar, the contact plate 330 is disposed in the path of travel of a tray for engagement thereby to swing the bar about the axis of the pivot pin 334 and actuate the switch 306. In such position of the bar, the tray is properly placed for scraping.

The member 322 is pivotally mounted on the frame, as at 343 in FIG. 5, so as to be lifted by a traveling tray to open the switch 312. As shown in FIG. 3, the member is also so spaced from the plate 318 that the member rides off of the trailing end of the tray and the switch closes as the tray is moving into proper position for scraping. When the switches 306 and 312 are in closed condition, the relay circuit is completed and the solenoids 102 and 108 are energized, resulting in stopping of the conveyor chain, rotation of the rotary disk 50, and movement of the wing plates 188 from retracted position.

The actuating bar 332 is in the path of movement of one of the wing plates I88, fragmentarily shown in FIG. 19, and is swung thereby about the axis of the pivot shaft 338 while in switch actuating position, that is, to the left of the position shown in FIG. 20. Such swinging of the bar moves the contact plate 330 out of the path of the tray, thus clearing the way for further travel of the tray.

As shown in FIG. 21, the bar carries a latching finger 344 and operatively related thereto is a latching lever 346 supported on a shaft 348 mounted for rotation on the frame. One end 350 of the lever is offset while the other end thereof is provided with a runner-like foot portion 352. A tension spring 354 interconnects the lever and the frame urging the foot portion downwardly. The foot portion is disposed in the path of the tray and is adapted to be lifted thereby for pivoting the lever to dispose the end 350 thereof in position to engage the latching finger, as shown in dashed lines in FIG. 20. This results from the aforementioned swinging of the bar and the bias of the spring 342. In the absence of a tray, the foot drops and the end 350 of the lever is lifted out of the way of the latching finger for permitting the bias of the spring to return the bar to normal position.

When the bar moves to latched position, the switch 306 returns to normally open position. However, in the meantime, the cam portion 320 on the rotary disk 50 has closed the switch 308 to maintain the relay and solenoids 102 and 108 energized during a half-revolution of the disk until the cam portion is disengaged from the switch and it returns to normally open condition. During its half-revolution, the disk 50 operates to swing the scraping device into engagement with a tray and to move the latching bar 58 to release, for rotation, the disk 52.

As shown in FIG. 22, the bar 58 has an end 356 carrying an upstanding pin 358 engaged by the latch 60, and an end 360 carrying an upstanding pin 362. The bar is of such a length that when the end 356 thereof is latched to the disk 52, the other end 360 thereof is adjacent to, but out of contact with, the disk 50, as shown in FIGS. 22 and 23. The bar 58 is supported in a pair of double plates 364 fixed to the frame portion and supporting the bar for endwise sliding movement and slight lifting of the ends thereof against the bias of a pair of compression springs 366. Each spring is individually supported in a spring guide and holder 368 suitably secured to the frame portion.

As shown in FIGS. 24 and 25, the latch 60 includes a laterally extending, arcuate lifting cam 372 adjacent to the periphery of the disk 50 and a cam member 374 radially inwardly thereof. The lifting cam has a leading ramp portion 376 which engages under the bar end 360 for lifting the same. The

cam 372 terminates in a rounded end 378 adjacent to a hollow or recess 380 formed in the disk 50 into which the bar end is adapted to move. Endwise movement is imparted to the bar by the cam member 374 which has an oblique camming surface 382 engageable with the pin 362 for moving the adjacent end 360 of the bar into the recess 380, as shown in FIG. 26. Thus, when the disk turns in the direction of the arrow 384, as shown in FIG. 25, the bar end 360 is moved into the recess, as shown in FIG. 24, and rides off the rounded end 378 of the lifting cam and drops to the bottom 386 of the recess, as shown in FIG. 25. The recess has radial dimensions such that when the bar end is in the bottom of the recess the pin 362 is below the lower edge of the cam 374, as shown in FIG. 26, and can clear the same for withdrawal of the bar. The bar end is thus engaged with the disk 50 for latching the same against rotation and for conditioning the latch for later disengagement.

The latch 60 on the disk 52 is structured with parts which are mirror images of corresponding parts of the latch 60 and function in a similar manner. A more detailed description thereof is therefore deemed unnecessary.

Accordingly, when the latch 60' operates to engage the latching bar to the disk 50, the bar is simultaneously disengaged from the disk 52 to release it for rotation. And, after one revolution of the disk 52, when the latch 60 operates to engage the latching bar thereto, the bar is simultaneously disengaged from the disk 50. The latches therefore operate alternately for sequential rotation of the disks and orderly operation of the scraping device.

Although this invention has been described in connection with an apparatus employing blades to perform a scraping operation, it will be appreciated it could employ jets discharging pressurized air or other fluid or abrasive particles for performing a treatment and that such description of the scraping embodiment is not to be considered as limiting the application of the invention.

OPERATION The operation of the scraping apparatus of the present invention is believed to be clearly apparent and is briefly summarized at this point. When the power is first turned on to put the several motors and conveyors into operation, the operating circuit is in the condition shown in FIG. 17 in which the relay 302 and the solenoids 102 and 108 are unenergized with the result that the brake drum 104 is stationary but the brake drum 98 is rotating and the conveyor chain 44 is moving in the direction of the arrow 46. A tray to be treated is then placed on the conveyor chain in a tilted dumping position as shown in FIG. 5, loose material on the tray gravitating onto the conveyor 124.

The tray is moved by the conveyor chain and, in due course, engages and lifts the member322 to open the switch 312. The tray then moves into the scraping station 38 and eventually engages the contact plate 330 to swing the actuating bar 332 about the axis of the pivot pin 334 against the bias of the spring 342 until the switch 306 is actuated to closed condition. In the meantime, the member 322 rides off the trailing end of the tray, restoring the switch 312 to closed condition. With both switches 306 and 312 closed, the relay and the solenoids are energized which results in the stopping of the brake drum 98 and the conveyor chain 44 and the release of the brake drum 104 for rotation.

Rotary power is then delivered to the differential gearing 62 which causes the rotary disk 50 to rotate since the disk 52 is held against rotation by engagement with the latching bar 58. With rotation of the disk 50, the scraping device is swung from its retracted position, as shown in FIG. 9, and the switch 308 is actuated to closed condition by the cam portion 320 on the disk 50 to establish a circuit for keeping the relay and solenoids energized.

In the meantime, the tray has engaged the foot portion 352 of the latching lever 346 to dispose the end 350 thereof in latching position. As the scraping device moves to the extended position thereof, as shown in FIG. 10, one of the wing plates 188 engages the actuating lever 332 causing it to swing about the axis of the pivot shaft 338, whereupon the contact plate 330 is withdrawn from the path of the tray and the wing plates pass by the end edges of the tray to insure that it is properly centered for scraping. The bar 332 is swung until the latching finger 344 carried thereby passes just beyond the end 350 of the latching lever, whereupon the spring 342 causes the bar to pivot to the right, as viewed in FIG. 18, for disposing the latching finger in the position shown in dashed lines in FIG. 20 and simultaneously relieving pressure on the actuating plate 318 for returning the switch 306 to normally open condition.

As the scraping device is extended into operative relation with the tray, the blades 232, 234 and 236 of each scraping mechanism engage the bottom of the tray with the pressure of the springs 254 urging the blades into scraping engagement, such pressure increasing as the blades move relative to the plates 224. As the blades move, such movement initially is transversely of the plates. However, as such movement increases, the bias of the springs 270 causes the end plates 232 and 236 to move endwardly as Well until the free distal ends thereof are in proximity to the bars 118 of the tray, the overlapping ends of the blades insuring full scraping between the bars.

With a half-revolution of the disk 50, the latch 60' thereon moves from the uppermost position, as shown in FIG. 22, to the lowermost position, as shown in FIG. 10, during which the latch engages the pin 362 and moves the latching bar end 360 into engagement with the disk, as shown in FIG. 24. Such engagement of the latching bar 58 with the disk 50 results in the disengagement of the bar end 356 from the disk 52, thus releasing the disk 52 for rotation. With disk 50 stopped and the disk 52 free to rotate, rotary power is transferred to the disk 52 and it turns one complete revolution before the latch 60 thereon re-engages the bar end 356 to the disk 52 and stops the rotation thereof.

During the first quarter turn of the disk 52, thrust is transmitted to the pitman 216 to swing the sector plate 210 and move the carriage member 192 and the scraping mechanisms 220 carried thereby to the right, as viewed in FIG. 12, a predetermined distance which places the right-hand scraping mechanism in proximity to the right wing plate 188. The next half-turn of the disk 52 exerts a pull on the pitman 216 to swing the sector plate and move the scraping mechanisms in the opposite direction a predetermined distance which places the left-hand scraping mechanism in proximity to the left-hand wing plate. The remaining quarter turn of the disk 52 returns the scraping mechanisms to the normal central position shown in FIG. 12.

With the completion of the revolution of the disk 52 and reengagement thereof with the latching bar 58, the latching bar is simultaneously disengaged from the disk 50 permitting it to rotate, whereupon rotary power is transferred thereto until another half-revolution thereof is completed and the cam portion 320 disengages from the switch 308, permitting it to return to normally open position. With both switches 306 and 308 open, the relay 302 is deenergized resulting in the deenergization of the solenoids 102 and 108, whereupon the spring 102 causes the brake drum 104 to stop, permitting rotation of the brake drum 98 and recommencement of movement of the conveyor chain 44.

Upon return of the scraping device to the retracted position thereof shown in FIG. 9, the scraping mechanisms 220 pass between the respective sets of bristles 282 which sweep or brush off any material adhering thereto. The fluid on the bristles serves to condition the blades for the next scraping operation by moistening them to minimize adherence of the tray material thereto.

With the resumption of movement of the conveyor chain, the tray is carried out of the scraping station, the foot portion 352 of the latching lever rides off the trailing end of the tray, whereupon the lever pivots and disengages the end 350 The conveyor chain then moves the cleaned tray into the discharge station 42 so that the leading end of the tray passes over the idler and engages the drive roller 144. The drive roller then takes over propulsion of the tray and advances it over the roller 142 until the leading end of the tray engages the switch 168 for closing a circuit, not shown, for energizing the solenoid 166 which operates the bell crank linkage to swing the kicker plate and move the tray 112 off of the rollers. The tray then gravitates onto the conveyor 138 which carries the lower end of the tray past the vertical position thereof generally shown in dashed lines in FIG. 8. This swings the tray and the upper end thereof trails the lower end and then gravitates to the conveyor 138 so that the tray is disposed thereon in material receiving position. In the meantime, with the discharge of the tray, the switch 168 returns to its normally open condition, solenoid 166 is deenergized and the spring 172 returns the kicker plate to normal position.

There has thus been provided a scraping apparatus which operates in a rapid and reliable manner for automatically cleaning material from trays and presenting them in substantially clean condition for receipt of further material, and which requires a minimum of attendants for the rapid and orderly operation thereof.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. An apparatus for cleaning trays comprising:

A. means for placing a tray in a predetermined position;

B. means responsive to the placement of the tray for cleaning the tray while in said position including,

1. tray centering means for maintaining the tray in a substantially motionless condition, and

2. tray cleaning means supported for movement into and out of operative engagement with said tray and for further movement transversely of the tray; and

C. actuating means coupled with said tray centering means and said tray cleaning means including,

1. a pair of spaced rotary members driven by differential gearing, and

2. reciprocable means disposed between the rotary members and alternately actuated thereby for alternately engaging the rotary members for alternately arresting rotation of the rotary members,

for moving the cleaning means into engagement with the tray,

for moving the tray cleaning means transversely of the tray and for retracting the cleaning means from engagement with the tray, whereby the tray is cleaned by the tray cleaning means while the tray is maintained in a substantially motionless condition by said tray centering means.

2. The apparatus of claim 1 in which the cleaning means includes a support frame pivotally mounted for swinging about a generally horizontal axis, and scraping elements mounted on the support frame for movement along paths generally parallel to said axis, link means interconnecting one of the rotary members with the support frame for swinging the same with each half-revolution of said member, and linkage including thereof from the latching finger 344, permitting the bias of the 75 crank means interconnecting the other of the rotary members with the scraping elements for imparting a cyclic motion thereto with each revolution of said member, the first halfrevolution of said one member operating to swing the frame to engage the scraping elements with the tray and to actuate the reciprocable means to arrest said one member and release the other member for initiation of its revolution of rotation, completion of the revolution of said other member operating to actuate the reciprocable means to arrest said other member and release said one member for swinging the support frame to a retracted position out of engagement with the tray.

3. The apparatus of claim 2 in which the reciprocable means is an elongated bar mounted for endwise movement having opposite ends adjacent to the rotary members respectively, and each rotary member has means engageable with the respective end of the bar for lifting it and moving the bar endwise in alternation.

4. The apparatus of claim 3 in which said last-named means includes a cam engageable with a pin on the respective bar end for pulling the bar end into arresting engagement with the respective member.

5. An apparatus for cleaning trays comprising:

A. means for placing a tray in a predetermined position with a surface thereof being arranged in'a generally upright disposition;

B. means responsive to the placement of the tray for cleaning the tray while it is in said position including a tray centering means and tray cleaning means, said tray cleaning means including,

l. a depending support frame mounted for swinging movement through a substantially vertical plane and about a generally horizontal. pivot axis between retracted and extended positions, said frame also being mounted for transverse movement along a path of movement generally paralleling the pivot axis, and

2. scraping elements engageable with said surface and carried by said frame along said path of movement,

said tray centering means being adapted to engage and maintain the tray in a substantially motionless condition; and

C. actuating means for imparting movement to the tray centering means and to the tray cleaning means, whereby the tray is cleaned while it is maintained in a substantially motionless condition by said tray centering means.

6. The apparatus of claim 5 further including means engageable with the scraping elements for conditioning the same for a scraping action.

7. The apparatus of claim 5 in which the scraping elements are mounted on the support frame for movement relative thereto and to each other for conforming to the configuration of the tray surface, and biasing means opposing such relative movement.

8. The apparatus of claim 5 in which the scraping elements include planar blades substantially linearly aligned in said plane and slidably mounted on the frame for movement relative thereto, one of said blades having an end overlapping the end of an adjacent blade and also movable endwise relative thereto, and resilient means mounted on the frame opposing relative movement between the blades and the frame operable upon stressing thereof to move the blades relative to each other for increasing their effective length.

9. The apparatus of claim 8 in which the resilient means includes springs pressing the backs of the blades and a springpressed lost motion mechanism connected to said one blade.

10. An apparatus for cleaning trays in which the trays are moved along a given path of travel comprising:

A. means for placing a tray in a predetennined position;

B. means responsive to the placement of the tray for cleaning the tray while in said position including,

1. tray centering means, and

2. tray cleaning means mounted for movement into and out of operative engagement with said tray,

said tray centering means being adapted to engage and maintain the tray in a substantially motionless condition and said tray cleaning means being adapted for further movement transversely of the tray while it is so engaged; and

C. actuating means for imparting said movement to the tray centering means and to the cleaning means including,

1. a movable member normally positioned in the path of travel of the tray and movable thereby to stop movement of the tray and initiate movement of the cleaning mechanism,

2. member moving means associated with said tray centering means operable upon movement thereof to move the member out of the path of travel of the tray, and

3. latching means operable to hold the member out of the path of travel of the tray, said latching means being conditioned for holding by movement of the tray to its predetermined position, movement of the tray from such position releasing the member for return to its normal position,

whereby the tray is cleaned while it is maintained in a substantially motionless condition by said tray centering means.

11. The apparatus of claim 10 in which the member includes a bar pivotally mounted for swinging about perpendicular axes and engageable by said part, and the latching means includes a latching finger on the bar and a pivoted latch lever, the lever being pivoted by the tray during movement thereof to position the lever for engagement with the latching finger after movement of the bar by the member moving means.

12. Apparatus for scraping trays and the like comprising a support, mobile means on the support for receiving a tray and conveying it along a path of travel to a predetermined point, scraping means mounted on the support for movement between retracted and extended positions, said scraping means in its extended position being engageable with the tray at the predetermined point thereof, and driven means on the support interconnecting the mobile means and scraping means operative sequentially to convey the tray to said predetermined point and to stop travel thereof, to extend the scraping means into engagement with the tray, to impart a scraping motion to the scraping means while the latter is engaged with the tray, to retract the scraping means, and to convey the tray away from said predetermined point.

13. The apparatus of claim 12 in which the driven means includes a first differential gearing connected to a source of power for differentially driving a first pair of rotary members, a second differential gearing for differentially driving a second pair of rotary members, one member of said first pair being connected to the second differential gearing and to a control device normally holding such member against rotation, the other member of said first pair being connected to said mobile means and to a control device normally permitting rotation of such member, the members of the second pair being connected to the scraping means for movement thereof between its positions and imparting a scraping motion thereto respectively, and means responsive to the positioning of the tray at said predetermined point for actuating the control devices for stopping the mobile means and simultaneously initiating rotation of one of the last-named members for moving the scraping means from its retracted position.

14. The apparatus of claim 13 in which said last-named members have associated therewith locking means including a reciprocable part normally locked to the other of said lastnamed members, said part being responsive to rotation of said one of the last-named members for locking thereto and unlocking from said other of the last-named members for holding the scraping means in extended position and initiating rotation of said other of the last-named members for imparting a scraping motion to the scraping means.

15. The apparatus of claim 14 in which said other of the last-named members is linked to the scraping means for imparting thereto a motion which moves the scraping means in one direction from a substantially central position, reverses the direction of movement and moves the scraping means past the substantially central position thereof, and returns the scraping means to its substantially central position, in sequence.

16. An apparatus for cleaning material from material carrying trays comprising a frame, conveying means on the frame 13 for conveying the tray to a cleaning station in a material dumping position, means supporting said tray in a substantially motionless condition at said cleaning station, cleaning means for cleaning material from a surface of the tray while the tray is supported in a substantially motionless condition at said cleaning station, orienting means for orienting the tray in a material receiving position, and drive means interconnecting said conveying means and said cleaning means with a common source of power for imposing thereon intermittent alternate actuation, said drive means including a pair of members alternately operable for sequentially operably relating the cleaning means with the tray, imparting a cleaning motion to the cleaning means, and retracting the cleaning means.

17. The apparatus of claim 16 in which the orienting means includes means engageable with the reverse side of the tray for imparting a force thereto which causes the tray to pivot about.

a generally horizontal axis so that the tray can gravitate to a position with the reverse side thereof on the bottom.

18. The apparatus of claim. 17 in which the drive means further includes differential gearing operatively connected to the conveying means and the pair of members, and brake means connected to the differential gearing for stopping the conveying means and transferring the drive of the source of power from the conveying means to the members.

19. The apparatus of claim 17 further including lock means mounted for reciprocatory movement and alternately locked to the members, operation of the members serving to impart reciprocatory movement to the last-named means.

20. The apparatus of claim 19 in which the lock means is an elongated bar disposed between the members, with the ends thereof adjacent thereto, and each member carries cam means operable to lift the adjacent end of the bar and impart endwise movement thereto toward the member.

l l ill l 

1. An apparatus for cleaning trays comprising: A. means for placing a tray in a predetermined position; B. means responsive to the placement of the tray for cleaning the tray while in said position including,
 1. tray centering means for maintaining the tray in a substantially motionless condition, and
 2. tray cleaning means supported for movement into and out of operative engagement with said tray and for further movement transversely of the tray; and C. actuating means coupled with said tray centering means and said tray cleaning means including,
 1. a pair of spaced rotary members driven by differential gearing, and
 2. reciprocable means disposed between the rotary members and alternately actuated thereby for alternately engaging the rotary members for alternately arresting rotation of the rotary members, for moving the cleaning means into engagement with the tray, for moving the tray cleaning means transversely of the tray and for retracting the cleaning means from engagement with the tray, whereby the tray is cleaned by the tray cleaning means while the tray is maintained in a substantially motionless condition by said tray centering means.
 2. tray cleaning means supported for movement into and out of operative engagement with said tray and for further movement transversely of the tray; and C. actuating means coupled with said tray centering means and said tray cleaning means including,
 2. reciprocable means disposed between the rotary members and alternately actuated thereby for alternately engaging the rotary members for alternately arresting rotation of the rotary members, for moving the cleaning means into engagement with the tray, for moving the tray cleaning means transversely of the tray and for retracting the cleaning means from engagement with the tray, whereby the tray is cleaned by the tray cleaning means while the tray is maintained in a substantially motionless condition by said tray centering means.
 2. The apparatus of claim 1 in which the cleaning means includes a support frame pivotally mounted for swinging about a generally horizontal axis, and scraping elements mounted on the support frame for movement along paths generally parallel to said axis, link means interconnecting one of the rotary members with the support frame for swinging the same with each half-revolution of said member, and linkage including crank means interconnecting the other of the rotary members with the scraping elements for imparting a cyclic motion thereto with each revolution of said member, the first half-revolution of said one member operating to swing the frame to engage the scraping elements with the tray and to actuate the reciprocable means to arrest said one member and release the other member for initiation of its revolution of rotation, completion of the revolution of said other member operating to actuate the reciprocable means to arrest said other member and release said one member for swinging the support frame to a retracted position out of engagement with the tray.
 2. scraping elements engageable with said surface and carried by said frame along said path of movement, said tray centering means being adapted to engage and maintain the tray in a substantially motionless condition; and C. actuating means for imparting movement to the tray centering means and to the tray cleaning means, whereby the tray is cleaned while it is maintained in a substantially motionless condition by said tray centering means.
 2. tray cleaning means mounted for movement into and out of operative engagement with said tray, said tray centering means being adapted to engage and maintain the tray in a substantially motionless condition and said tray cleaning means being adapted for further movement transversely of the tray while it is so engaged; and C. actuating means for imparting said movement to the tray centering means and to the cleaning means including,
 2. member moving means associated with said tray centering means operable upon movement thereof to move the member out of the path of travel of the tray, and
 3. latching means operable to hold the member out of the path of travel of the tray, said latching means being conditioned for holding by movement of the tray to its predetermined position, movement of the tray from such position releasing the member for return to its normal position, whereby the tray is cleaned while it is maintained in a substantially motionless condition by said tray centering means.
 3. The apparatus of claim 2 in which the reciprocable means is an elongated bar mounted for endwise movement having opposite ends adjacent to the rotary members respectively, and each rotary member has means engageable with the respective end of the bar for lifting it and moving the bar endwise in alternation.
 4. The apparatus of claim 3 in which said last-named means includes a cam engageable with a pin on the respEctive bar end for pulling the bar end into arresting engagement with the respective member.
 5. An apparatus for cleaning trays comprising: A. means for placing a tray in a predetermined position with a surface thereof being arranged in a generally upright disposition; B. means responsive to the placement of the tray for cleaning the tray while it is in said position including a tray centering means and tray cleaning means, said tray cleaning means including,
 6. The apparatus of claim 5 further including means engageable with the scraping elements for conditioning the same for a scraping action.
 7. The apparatus of claim 5 in which the scraping elements are mounted on the support frame for movement relative thereto and to each other for conforming to the configuration of the tray surface, and biasing means opposing such relative movement.
 8. The apparatus of claim 5 in which the scraping elements include planar blades substantially linearly aligned in said plane and slidably mounted on the frame for movement relative thereto, one of said blades having an end overlapping the end of an adjacent blade and also movable endwise relative thereto, and resilient means mounted on the frame opposing relative movement between the blades and the frame operable upon stressing thereof to move the blades relative to each other for increasing their effective length.
 9. The apparatus of claim 8 in which the resilient means includes springs pressing the backs of the blades and a spring-pressed lost motion mechanism connected to said one blade.
 10. An apparatus for cleaning trays in which the trays are moved along a given path of travel comprising: A. means for placing a tray in a predetermined position; B. means responsive to the placement of the tray for cleaning the tray while in said position including,
 11. The apparatus of claim 10 in which the member includes a bar pivotally mounted for swinging about perpendicular axes and engageable by said part, and the latching means includes a latching finger on the bar and a pivoted latch lever, the lever being pivoted by the tray during movement thereof to position the lever for engagement with the latching finger after movement of the bar by the member moving means.
 12. Apparatus for scraping trays and the like comprising a support, mobile means on the support for receiving a tray and conveying it along a path of travel to a predetermined point, scraping means mounted on the support for movement between retracted and extended positions, said scraping means in its extended position being engageable with the tray at the predetermined point thereof, and driven means on the support interconnecting the mobile means and scraping means operative sequentially to convey the tray to said predetermined point and to stop travel thereof, to extend the scraping means into engagement with the tray, to impart a scraping motion to the scraping means while the latter is engaged with the tray, to retract the scraping means, and to convey the tray away from said predetermined point.
 13. The apparatus of claim 12 in which the driven means includes a first differential gearing connected to a source of power for differentially driving a first pair of rotary members, a second differential gearing for differentially driving a second pair of rotary members, one member of said first pair being connected to the second differential gearing and to a control device normally holding such member against rotation, the other member of said first pair being connected to said mobile means and to a control device normally permitting rotation of such member, the members of the second pair being connected to the scraping means for movement thereof between its positions and imparting a scraping motion thereto respectively, and means responsive to the positioning of the tray at said predetermined point for actuating the control devices for stopping the mobile means and simultaneously initiating rotation of one of the last-named members for moving the scraping means from its retracted position.
 14. The apparatus of claim 13 in which said last-named members have associated therewith locking means including a reciprocable part normally locked to the other of said last-named members, said part being responsive to rotation of said one of the last-named members for locking thereto and unlocking from said other of the last-named members for holding the scraping means in extended position and initiating rotation of said other of the last-named members for imparting a scraping motion to the scraping means.
 15. The apparatus of claim 14 in which said other of the last-named members is linked to the scraping means for imparting thereto a motion which moves the scraping means in one direction from a substantially central position, reverses the direction of movement and moves the scraping means past the substantially central position thereof, and returns the scraping means to its substantially central position, in sequence.
 16. An apparatus for cleaning material from material carrying trays comprising a frame, conveying means on the frame for conveying the tray to a cleaning station in a material dumping position, means supporting said tray in a substantially motionless condition at said cleaning station, cleaning means for cleaning material from a surface of the tray while the tray is supported in a substantially motionless condition at said cleaning station, orienting means for orienting the tray in a material receiving position, and drive means interconnecting said conveying means and said cleaning means with a common source of power for imposing thereon intermittent alternate actuation, said drive means including a pair of members alternately operable for sequentially operably relating the cleaning means with the tray, imparting a cleaning motion to the cleaning means, and retracting the cleaning means.
 17. The apparatus of claim 16 in which the orienting means includes means engageable With the reverse side of the tray for imparting a force thereto which causes the tray to pivot about a generally horizontal axis so that the tray can gravitate to a position with the reverse side thereof on the bottom.
 18. The apparatus of claim 17 in which the drive means further includes differential gearing operatively connected to the conveying means and the pair of members, and brake means connected to the differential gearing for stopping the conveying means and transferring the drive of the source of power from the conveying means to the members.
 19. The apparatus of claim 17 further including lock means mounted for reciprocatory movement and alternately locked to the members, operation of the members serving to impart reciprocatory movement to the last-named means.
 20. The apparatus of claim 19 in which the lock means is an elongated bar disposed between the members, with the ends thereof adjacent thereto, and each member carries cam means operable to lift the adjacent end of the bar and impart endwise movement thereto toward the member. 